Without limiting the scope of the invention, its background is described in connection with silanes. Silanes including mercaptosilanes are very reactive compounds and this reactivity causes the compositions to be difficult to synthesize and particularly difficult to use in preparing filled elastomer compositions. The chemoselective reaction of chlorosilanes with mercaptoalcohols has been reported (Wada, M. et al, Journal of Organometallic Chemistry 1972, 39, 99-106); however, these compounds contained a single thiol group. Since that time, several articles have described the preparation of similar single-thiol compounds.
For example, U.S. Pat. No. 8,008,519, entitled, “Process for Making Mercapto-Functional Silane,” discloses organofunctional silanes and mixtures of organofunctional silanes possessing mercaptan and hydrocarbyl and/or heterocarbyl functionality. These silanes reduce or eliminate the generation of volatile organic compounds during use, aid in the processing of filled elastomeric materials, and enhance the end-use properties of the filled elastomer.
Examples of alkoxysilanes and oligomeric alkoxysiloxanes can be seen in U.S. Pat. No. 5,183,914, entitled, “Alkoxysilanes and Oligomeric Alkoxysiloxanes by a Silicate-Acid Route,” disclose a method of preparing alkoxysilanes and oligomeric alkoxysiloxanes by reacting a metal silicate with an acid selected from the group consisting of sulfurous acid and acids with a pKa greater than about 2.5 in the presence of an alcohol. The resultant product is then reacted with an alcohol to form the alkoxysilane or oligomeric alkoxysiloxane, depending on the starting silicate.
An article published in a German journal (Becker, B. et al, Zeitschrift fur anorganische and allgemeine Chemie 1982, 488, 229-234) lists several di-thiol compounds as part of a larger library of compounds but without detailed experimental and characterization data.
A recent patent (WO 2009/132265) describes degradable compounds that possess a silicon bonded to two oxygen atoms; however, the general descriptions include compositions having a different structure and properties and would not include the compounds of the present invention.